Dragon Ball Z II: Gekishin Freeza!!

This page contains notes for the game Dragon Ball Z II: Gekishin Freeza!!.

Version Differences#

BANDAI'91 D·B·Z-2 PRG (CRC32: 1582FEE0)

0F/CB79: 20 73 CD      jsr $CD73 ; set VRAM mirroring and CHR ROM banks
0F/CB7C: A5 47         lda $47
0F/CB7E: 8D 01 20      sta $2001 ; PPUMASK

BANDAI '91 D·B·Z·2 PRG VER2 (CRC32: E49FC53E)

0F/CB79: A5 47         lda $47
0F/CB7B: 8D 01 20      sta $2001 ; PPUMASK
0F/CB7E: 20 73 CD      jsr $CD73 ; set VRAM mirroring and CHR ROM banks

This code, which is the only change between the two ROM versions, is part of the NMI routine. The original version first calls a subroutine that writes to the mapper VRAM mirroring and CHR banking registers, and then writes to the PPU register $2001. The revised ROM reverses the order of these two operations, writing to $2001 first. This change ensures that the PPU register write happens inside vblank even on a busy frame when the game is doing a lot of VRAM updates.